1. Field of the Invention
The present invention relates to connectors. More specifically, the present invention relates to connectors that include wafers.
2. Description of the Related Art
Connectors are used to place electrical devices in communication with one another, and right-angle connectors are often used to connect an electrical device or cable to a circuit board. An example of a right-angle connector 101 that is mounted to a circuit board 120 using weld tabs 130 is shown in FIGS. 1-3. As shown in FIG. 1, the right-angle connector 101 includes wafers 110 with wafer legs 112 that are electrically connected to pads 121 of the circuit board 120. Interior ones of the wafers 110 are not shown in FIG. 1 for clarity. The right-angle connector 101 is aligned to the circuit board 120 by alignment pins 103 that are molded into the body 102 of the right-angle connector 101 and alignment holes 122 of the circuit board 120. As shown in the cross-sectional view of FIG. 2, the weld tabs 130 pass through tab holes 104 of the right-angle connector 101 to engage with weld holes 123 of the circuit board 120 to secure the right-angle connector 101 to the circuit board 120 and to reduce stresses applied to solder joints between the wafer legs 112 and the pads 121 of the circuit board 120. These solder joints are provided by solder 119 that is attached to the wafer legs 112 and then reflowed after the right-angle connector 101 is mounted to the circuit board 120 to provide electrical connections between the wafer legs 112 and the pads 121. FIG. 3 shows the wafer legs 112 and the weld tabs 130 respectively engaged with the pads 121 and the weld holes 123, with the connector body 102 removed for clarity.
However, in right-angle connector 101, the weld tabs 130 do not provide alignment for the wafers 110 and do not retain the wafers 110 within the right-angle connector body 102. Further, since the weld tabs 130 are separate elements that individually secure the right-angle connector 101 to the circuit board 120, large manufacturing tolerances are required for the right angle connector 101, the wafers 110, and the circuit board 120 due to a high probability of alignment inaccuracies between the right-angle connector 101 and circuit board 120.
Furthermore, due to the geometrical structure of the right-angle connector 101, the connector body 102 has a tendency to twist along its longitudinal or lengthwise axis, for example, when exposed to high temperatures during soldering of the wafer legs 112 to the pads 121 of the circuit board 120. As shown in FIGS. 1 and 3, adjacent ones of the wafers 110 do not interlock with each other and thus do not resist the twisting of the connector body 102. Accordingly, any twisting of the connector body 102 may affect the alignment of the wafer legs 112, for example, by causing the bottom surfaces of the wafer legs 112 to not be co-planar which results in poor electrical connections between the wafer legs 112 and the pads 121 of the circuit board 120. Furthermore, poor electrical connections between the wafer legs 112 and the pads 121 of the circuit board 120 may also arise from the bottom surfaces of the solder 119 not being co-planar, for example, due to the above-described twisting of the connector body 102 or the solder 119 being unevenly applied to neighboring wafer legs 112.
When the right-angle connector 101 is mounted to the circuit board 120, the optimal location for each of the wafer legs 112 is centered above its corresponding pad 121. However, since the solder 119 is attached to the sides of the wafer legs 112, the solder 119 is offset from the center of their corresponding pads 121. Accordingly, the pads 121 have oblong (e.g., ovaloid) shapes so that the wafer legs are centered and the solder 119 is able to contact their corresponding pads 121 without bleeding solder onto neighboring pads 121 when the solder 119 is reflowed.